Objective:

This study has three objectives: (1) establish a
baseline of microbial community structure and
composition within sea ice, including members
of the rare biosphere who may have bioremediation
potential; (2) search for genes known to be
involved in the degradation of crude oil within
several different components of the sea ice
environment; and (3) determine the prevalence
of these genes within the active segment of the
microbial community.

Approach:

DNA will be extracted from samples of first year
ice, young sea ice, marine water and surface ice
features (known to be microbial enriched) from
McMurdo Sound, Antarctica. Pending additional
field opportunities, samples also may be collected
from Barrow, Alaska or Nuuk, Greenland. Purified
DNA from these samples will be amplified for the
V6 hypervariable region of the 16S rRNA gene and sequenced in a massively parallel fashion using
the paired-end technique on either the SOLiD
or Illumina sequencing platforms. Both of these
platforms support sufficient multiplexing to allow
replication, yet still allow for great sequencing
depth (tens of millions of reads per sample). Taxonomic
and phylogenetic analysis of assembled
paired-ends, and community description with
standard ecological indices will establish a valuable
baseline of the sea ice microbial community.
Amplification of the purified DNA with primers
specific to genes marking known pathways for the
degradation of crude oil components, followed
by clone library and T-RFLP analysis will characterize
the bioremediation potential of the sea
ice microbial community. Amplification of these
same genes from sea ice microcosms labeled with
heavy carbon substrates (stable isotope probing,
or SIP) will determine to what extent these genes
are contained within an active segment of the
microbial community, and thus are available for
rapid bioremediation.

Expected Results:

Due to the concentrating effects of eutectic freezing,
sea ice brines are considered to be an organic
rich environment. Microbes adapted to life in
sea ice should be capable of living under these
conditions and degrading a wide range of organic
compounds. Because of this, the expectation is to
find that the sea ice microbial community is able
to consume a broad range of organic compounds
found in crude oil. If this is the case, then sea ice
might serve as the seedbank for a community of
oil degrading organisms in the case of an oil spill
at high latitudes.

Potential to Further Environmental Human Health Protection

Increasing oil exploration in the Arctic, and the
potential for exploration in the Antarctic, raise
the risk of a release of crude oil in ice covered
seas. This project provides valuable information
on the potential of the sea ice microbial
community to bioremediate released crude oil.

Supplemental Keywords:

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.